Thread: fix type and add BOOST_THREAD_USE_ATOMIC macro doc.

git-svn-id: http://svn.boost.org/svn/boost/trunk@85432 b8fc166d-592f-0410-95f2-cb63ce0dd405
Replacing boost::conditional with boost::bool_.

git-svn-id: http://svn.boost.org/svn/boost/trunk@85433 b8fc166d-592f-0410-95f2-cb63ce0dd405
Changed "not" to "!" for MSVC compatibility.

git-svn-id: http://svn.boost.org/svn/boost/trunk@85434 b8fc166d-592f-0410-95f2-cb63ce0dd405
Remove duplicate 1.6 notes.

git-svn-id: http://svn.boost.org/svn/boost/trunk@85435 b8fc166d-592f-0410-95f2-cb63ce0dd405
small bugfix when calculating v plane offset.

git-svn-id: http://svn.boost.org/svn/boost/trunk@85436 b8fc166d-592f-0410-95f2-cb63ce0dd405
add missing cctype #include to fix msvc build

git-svn-id: http://svn.boost.org/svn/boost/trunk@85438 b8fc166d-592f-0410-95f2-cb63ce0dd405